1. Field of the Invention
The present invention relates to a shaft clamping member comprising first and second halves each of which has mating faces at circumferential opposite ends of a semi-circular recess, the first and second halves being fastened to each other by a plurality of threaded members in a state where the mating faces of both the halves are matched to each other to define a shaft-receiving hole by both the semi-circular recesses, and processes for producing the same.
2. Description of the Prior Art
Conventionally known shaft clamping members of a construction similar to that described above include a connecting rod for an internal combustion engine, comprised of a first half which is a rod member having a smaller end portion at one end and a semi-annular portion for a large end portion at the other end, and a second half which is a semi-annular cap fastened to the semi-annular portion of the rod member by threaded members, e.g., bolts, to form the connecting rod which can be mounted on or removed from a chank pin portion of the crankshaft of the engine.
In general, the connecting rod for an internal combustion engine is conventionally formed from a carbon steel for a strong mechanical structure.
As one countermeasure for accommodating an environmental problem, a reduction in fuel consumption in an internal combustion engine for vehicle is demanded. To meet this, a reduction in weight of a structural member, especially, a moving part, is effective. In this case, a reduction in the weight of the connecting rods, which are moving parts, provides a large effect in reduction of fuel consumption. It is desirable to develop a lightweight and inexpensive connecting rod, in place of the conventional connecting rod made of steel.
Thus, it would be desirable to form a connecting rod from an aluminum alloy, which is a light alloy, from the demand for the reductions in weight and cost.
However, a connecting rod of aluminum alloy is resiliently deformed under relatively low stress due to the fact that aluminum alloy has a lower rigidity than that of a steel. Therefore, a misalignment in a direction parallel to the mating faces of the rod member and the cap is liable to be produced between the mating faces. This results in a condition whereby the stress is received by only the rod member, and hence, the life of the rod member is considerably shortened.
To overcome the above disadvantage, it is effective to increase the axial tension of the bolt. However, if such a means is employed, a new problem arises that a seat surface of the bolt head is depressed, because the aluminum alloy has a lower rigidity and a lower creep strength than those of the steel bolt.